The Gases that make possible the life of living things Are found in the atmosphere, which is the layer of gases that surrounds the Earth and is kept around the planet by the effect of gravity.
This atmosphere protects life on earth by absorbing the ultraviolet light that is emitted by the sun. Another function is to maintain the temperature stable on the surface, through the greenhouse effect and reducing extreme temperature variations during the day and night.
The gases that make up the atmosphere are mainly nitrogen and oxygen, although it also has other components such as carbon dioxide, argon, water vapors and small amounts of other compounds.
It is believed that the atmosphere was formed 4.5 billion years ago along with the development of the planet and that the first atmosphere was the product of the gases that escaped from the interior of the Earth. It is likely that the first atmosphere would consist mostly of carbon dioxide and water vapor, with a small proportion of ammonia NH3.
It was later the process of photosynthesis of green plants which increased the percentage of oxygen in the atmosphere, to reach more than 20% as it is today.
Currently the pollution produced by human activities has caused that the concentrations of these gases change and with this will generate different effects on the surface of the Earth.
The gases necessary for the life of living beings
The gases that are found in the Earth's atmosphere in greater quantities and are essential for life on Earth are the following:
Nitrogen is found in a volume of 78% in the atmosphere. One of its functions is to dilute the oxygen present and thereby prevent the atmosphere from catching on the surface of the earth. It is critical to the creation of proteins that are fundamental to living things.
Nitrogen has a cycle in which it is transformed into different organic compounds, one of the most important processes for the subsistence of living beings. During this nitrogen cycle, bacteria in soil processes or converts atmospheric nitrogen into ammonia, a compound necessary for plants and their growth.
Other bacteria also convert ammonia into amino acids and proteins. Then the animals consume the plants and thus introduce these proteins. Finally, the bacteria also convert nitrogen waste into nitrogen gas, and thus return to the atmosphere.
However, an excess of nitrogen such as we have seen from the overuse of nitrogen-based fertilizers contributes to water pollution and to the climate change process currently under way on the planet.
Oxygen is available in 21% in the Earth's atmosphere and is used by all living beings as it is the essential gas for breathing. It is also one of the fundamental elements for the combustion and ignition of materials.
The presence of oxygen in the earth is supported by the oxygen cycle, which involves the movement of oxygen between air, living things and Earth's crust. There is 47% oxygen in the earth's crust and is one of the three most common elements in the universe, along with helium and hydrogen.
The process of photosynthesis in which through the action of plants the carbon dioxide is converted into oxygen, is fundamental for the presence of oxygen on Earth.
Ozone O3, is a different form of oxygen that combines three atoms of gas together. The ozone layer provides protection against harmful ultraviolet radiation from the sun. Due to atmospheric pollution, this layer has been weakening.
This gas is present in the incandescent bulbs. It is one of the derivatives of potassium and it is thought that because of the important presence of potassium in the Earth's lithosphere, the atmosphere has an amount of 0.93% argon.
There is 0.03% of carbon dioxide present in the atmosphere. This happens because all living things - plants and animals - release energy from their food through breathing. It is respiration and combustion which releases carbon dioxide into the atmosphere.
This process is known as a carbon cycle, in which the proportion of carbon dioxide in the atmosphere always stays the same.
One of the functions of carbon dioxide is to prevent the temperature of the planet from escaping and causing a cooling phenomenon. However, the excessive use of polluting fossil fuels is generating a dangerous increase of carbon dioxide in the air.
On the other hand, the urbanization of the territories and the logging of forests and forests for the creation of farms, crops and cities, is generating a reduction of green areas with plants that can carry out their process of photosynthesis and convert this excess of carbon dioxide In oxygen. This increases the presence of pollutants in the atmosphere.
The water vapor is present in a percentage of 0.25%. We know that the atmosphere is not always the same concentration. According to the presence of wind, the percentage of gases in the air composition varies slightly with altitude and location.
This occurs especially with water vapor, which, for example, in deserts at very low temperatures, is only 0.1% by volume. On the other hand, in hot and humid areas, air can contain up to 6% water vapor.
In the colder areas of the atmosphere, we find much less water vapor than in warm, moist air masses on the surface of the earth.
Traces of other compounds
Other gases are also found within the gases that are fundamental to life, but in very small concentrations. These are neon gas, krypton, xenon, helium and also methane.
In addition to this, in the air we find spores, dust particles and currently pollutants such as carbon monoxide, nitrogen oxides and sulfur dioxide.
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